P1602Manufacturer-specific code

P1602 Code: Low Voltage at Engine Computer Power Supply, Terminal 30 (Volkswagen)

On Volkswagen, Audi, Seat and Skoda vehicles, the P1602 code means the voltage at the computer power supply (terminal 30) was too low. You may notice slow cranking. Other brands may define this number differently.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$0 to $250
Difficulty
Easy
System
Computer and Outputs
Applies to
Depends on the manufacturer

Common in: Audi, Seat, Volkswagen

Updated Reviewed by Renzo Chacca

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What the P1602 code means

P1602 is a manufacturer-specific code: the 1 in the second position means each automaker defines what it means, not the generic SAE standard. The most widespread definition is the one used by Volkswagen, Audi, Seat and Skoda. If your vehicle is another brand, confirm the code text with a scan tool that supports that manufacturer.

ManufacturerMeaning of P1602
Volkswagen, Audi, Seat and SkodaLow voltage at the computer power supply (terminal 30)

Terminal 30 is the constant power feed from the battery. The computer records the voltage it is running on.

The P1602 code shows up when that voltage was too low: a weak battery, loose terminals or a start with a drained battery.

Before you start repairs, confirm the make, model, year and engine. With manufacturer codes, the same number can change even between engines from the same brand.

P1602 code symptoms

  • Check engine light on.
  • Slow cranking.
  • Other modules with voltage codes.

Likely causes of the P1602 code

  1. Weak battery. Confirm it with the tests in the diagnosis section.
  2. Loose or sulfated terminals. Confirm it with the tests in the diagnosis section.
  3. Alternator. Confirm it with the tests in the diagnosis section.
  4. Engine ground. Confirm it with the tests in the diagnosis section.

How to diagnose the P1602 code step by step

  1. Test the battery.
  2. Measure the charging voltage.
  3. Check the terminals and grounds.

How to fix the P1602 code

  • Replace the battery or repair the charging system.
  • Clear the code.

Technical reference data

  • Resting voltage: 12.4 to 12.7 V.
  • P1xxx codes are manufacturer-specific: confirm the definition with a scan tool that supports your brand.
  • Reference values: check the manufacturer data for your vehicle.

Brand-specific notes

Low voltage often sets codes in several modules at once, so start with the battery before you chase individual parts.

P1602 on Volkswagen Group

Common on the Volkswagen Golf, Jetta, Bora, Polo and Passat, the Audi A3 and A4, and the Seat Ibiza and Leon.

If your vehicle is another brand, check the table above for the meaning its manufacturer gives this code and confirm it with a compatible scan tool.

Frequently asked questions about P1602

What does the P1602 code mean on a Volkswagen?
It means the voltage at the computer power supply (terminal 30) was too low. You may notice slow cranking.
Does P1602 mean the same thing on every brand?
No. It is a manufacturer-specific code, so on other brands it may not exist or may mean something different. Confirm it with a scan tool that supports your make.
Can I drive with a P1602 code?
Yes. With a P1602 code severity is low and the vehicle normally drives as usual. Have the battery tested soon so it does not leave you stranded.
How much does it cost to fix P1602?
Roughly $0 to $250 on a Volkswagen. Tightening a terminal costs nothing, while a new battery or alternator costs more.
Will a P1602 code clear itself?
It may stay off if the voltage dip was a one-time event. If the battery or charging system is weak, the code returns.
What is the most common cause of P1602?
A weak battery. Loose or sulfated terminals, the alternator and the engine ground come next.

Related codes

Questions about the P1602 code

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